TMSS-142: initial implementation of validation of subtask specification against its schema

SAS/TMSS/src/tmss/tmssapp/models/scheduling.py

@@ -8,6 +8,13 @@ from django.contrib.postgres.fields import ArrayField, JSONField
 from .specification import AbstractChoice, BasicCommon, Template, NamedCommon # , <TaskBlueprint
 from enum import Enum
 from rest_framework.serializers import HyperlinkedRelatedField
+
+from lofar.sas.tmss.tmss.exceptions import *
+
+import json
+import fastjsonschema
+import jsonschema
+
 #
 # I/O
 #
@@ -127,7 +134,6 @@ class DataproductFeedbackTemplate(Template):
 #
 # Instance Objects
 #
-
 class Subtask(BasicCommon):
     """
     Represents a low-level task, which is an atomic unit of execution, such as running an observation, running
@@ -147,6 +153,21 @@ class Subtask(BasicCommon):
     scheduler_input_doc = JSONField(help_text='Partial specifications, as input for the scheduler.')
     # resource_claim = ForeignKey("ResourceClaim", null=False, on_delete=PROTECT) # todo <-- how is this external reference supposed to work?
 
+    def validate_specification_against_schema(self):
+        try:
+            # ensure the specification and schema are both valid json in the first place
+            spec = json.loads(self.specifications_doc) if type(self.specifications_doc) == str else self.specifications_doc
+            schema = json.loads(self.specifications_template.schema) if type(self.specifications_template.schema) == str else self.specifications_template.schema
+            jsonschema.validate(spec, schema)
+        except Exception as e:
+            raise SpecificationException(str(e))
+
+    def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
+        '''override of normal save method, doing a validation of the specification against the schema first
+        :raises SpecificationException in case the specification does not validate against the schema'''
+        self.validate_specification_against_schema()
+        super().save(force_insert, force_update, using, update_fields)
+
 
 class SubtaskInput(BasicCommon):
     subtask = ForeignKey('Subtask', null=False, on_delete=CASCADE, help_text='Subtask to which this input specification refers.')